MIN_CONTIG_ORDER
static unsigned int discontig_frames_order = MIN_CONTIG_ORDER;
static unsigned long discontig_frames_early[1UL << MIN_CONTIG_ORDER] __initdata;
BUG_ON(order < MIN_CONTIG_ORDER);
order - MIN_CONTIG_ORDER);
free_pages((unsigned long)old_array, old_order - MIN_CONTIG_ORDER);
if (alloc_discontig_frames(MIN_CONTIG_ORDER))